JP2004230141A - Guide wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guide wire excellent in the operability and kink-resistance with gentle change of the rigidity in the longitudinal direction of the wire. <P>SOLUTION: The guide wire 1 comprises a first linear wire 2 disposed on the distal side and the second linear wire 3 disposed on the proximal end side, and formed from a material having a elastic modulus higher than that of the first wire 2. The first wire 2 and the second wire 3 are connected by welding, and the second wire 3 has a small cross-section area part 32 whose area of the cross section is smaller than that of the base end part 23 of the first wire 2 near the welded part 14 with the first wire 2. The outer diameter of the small cross-section area part 32 becomes gradually smaller toward the distal end. The first wire 2 is preferably made of a superelastic alloy, and the second wire 3 is preferably made of stainless steel. The welding of the first wire 2 and the second wire 3 is preferably butt resistance welding. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a guidewire, particularly to a guidewire used for introducing a catheter into a body cavity such as a blood vessel.
[0002]
[Prior art]
The guide wire is used for treatment of a site where surgery is difficult, such as PTCA (Percutaneous Transluminal Coronary Angioplasty), treatment for the purpose of minimally invasive to the human body, and treatment of the heart. It is used to guide catheters used for examinations such as angiography. The guide wire used in the PTCA operation is inserted into the vicinity of a target vascular stenosis together with the balloon catheter with the distal end of the guide wire protruding from the distal end of the balloon catheter. Guide to nearby.
[0003]
The blood vessels are intricately curved, and the guide wire used when inserting the balloon catheter into the blood vessels has a moderate flexibility and resilience to bending, and a pushability to transmit the operation at the proximal end to the distal side. And torque transmission properties (collectively referred to as “operability”), as well as kink resistance (bending resistance) and the like. Among these properties, as a structure for obtaining a moderate flexibility, a structure with a metal coil that has flexibility against bending around a thin tip core material of a guide wire, and for imparting flexibility and resilience There is a guide wire using a superelastic wire such as Ni-Ti as a core material.
[0004]
In a conventional guide wire, a core material is substantially composed of one kind of material. In order to enhance the operability of the guide wire, a material having a relatively high elastic modulus is used. Has lost flexibility. If a material having a relatively low elastic modulus is used to obtain the flexibility of the distal end portion of the guide wire, the operability at the proximal end side of the guide wire is lost. Thus, it has been difficult to satisfy the required flexibility and operability with one kind of core material.
[0005]
In order to improve such a defect, for example, a Ni—Ti alloy wire is used as a core material, and heat treatment is performed on the distal side and the proximal side under different conditions to increase the flexibility of the distal end and increase the flexibility of the proximal side. A guide wire with increased rigidity has been proposed (for example, see Patent Document 1). However, there is a limit to the control of flexibility by such heat treatment, and even if sufficient flexibility is obtained at the distal end, satisfactory rigidity may not always be obtained at the proximal end.
[0006]
[Patent Document 1]
JP-A-63-171570
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a guidewire which has a gradual change in rigidity in the longitudinal direction of the wire and is excellent in operability and kink resistance.
[0008]
[Means for Solving the Problems]
Such an object is achieved by the present invention described in the following (1) to (11). Further, the following (12) to (22) are preferable.
[0009]
(1) a linear first wire disposed on the distal end side;
A linear second wire, which is disposed on the base end side of the first wire and is made of a material having a higher elastic modulus than the constituent material of the first wire,
The first wire and the second wire are connected by welding,
The second wire has a small cross-sectional area near the weld of the first wire and the second wire, the cross-sectional area of which is smaller than the cross-sectional area of the base end of the first wire. Guide wire.
[0010]
(2) a linear first wire disposed on the distal end side;
A second linear wire disposed on the proximal end side of the first wire and having a higher rigidity than the first wire;
A welding portion where the first wire and the second wire are connected by welding, having a projecting portion projecting in an outer peripheral direction;
The second wire has a small cross-sectional area near the weld of the first wire and the second wire, the cross-sectional area of which is smaller than the cross-sectional area of the base end of the first wire. Guide wire.
[0011]
(3) The guide wire according to the above (1) or (2), further comprising a coating layer provided so as to cover at least the welded portion.
[0012]
(4) The guide wire according to any one of (1) to (3), wherein an outer diameter of the small cross-sectional area is smaller than an outer diameter of a base end of the first wire.
[0013]
(5) The guidewire according to any one of (1) to (4), wherein the small cross-sectional area portion has a portion whose cross-sectional area gradually decreases in a distal direction.
[0014]
(6) The guide wire according to any one of (1) to (5), wherein the small cross-sectional area portion has a portion whose outer diameter gradually decreases in a distal direction.
[0015]
(7) The small cross-sectional area portion has a first portion whose outer diameter gradually decreases in the distal direction, and is located closer to the distal side than the first portion, and the outer diameter gradually increases in the distal direction. The guidewire according to any one of the above (1) to (5), having a second portion.
[0016]
(8) The guide wire according to (7), wherein the small cross-sectional area portion has a third portion having a substantially constant outer diameter between the first portion and the second portion.
[0017]
(9) The guidewire according to (7) or (8), wherein the length of the first portion is 0.1 to 1000 times the length of the second portion.
[0018]
(10) The guide wire according to any one of (1) to (9), wherein a bending rigidity at a distal end of the second wire and a bending rigidity at a proximal end of the first wire are substantially equal.
[0019]
(11) The guidewire according to any one of (1) to (10), further including a step filling member that fills a step formed on the outer periphery of the welded portion.
[0020]
(12) The guide wire according to (7), wherein an outer peripheral surface at a boundary between the first portion and the second portion forms a continuous curved surface without a step.
[0021]
(13) The outer peripheral surface at the boundary between the first portion and the third portion and the outer peripheral surface at the boundary between the third portion and the second portion are each continuously curved without a step. The guidewire according to the above (8), which constitutes a surface.
[0022]
(14) The guide wire according to any of (1) to (13), wherein the first wire is made of a superelastic alloy.
[0023]
(15) The guide wire according to any one of (1) to (14), wherein the second wire is made of stainless steel.
[0024]
(16) The guide wire according to any one of (1) to (15), wherein the second wire is made of a Co-based alloy.
[0025]
(17) The guide wire according to (16), wherein the Co-based alloy is a Co-Ni-Cr-based alloy.
[0026]
(18) The guide wire according to any one of (1) to (17), wherein a connection end face between the first wire and the second wire is substantially perpendicular to an axial direction of both wires.
[0027]
(19) The guide wire according to any one of (1) to (18), further including a spiral coil that covers at least a portion of the first wire on the distal end side.
[0028]
(20) The guide wire according to the above (19), wherein the welded portion is located closer to a base end than a base end of the coil.
[0029]
(21) The guidewire according to any one of (1) to (20), wherein the welding is performed by butt resistance welding.
[0030]
(22) The guidewire according to any one of (1) to (21), wherein the welded portion is used so as to be located in a living body.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a guidewire of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
[0032]
<First embodiment>
FIG. 1 is a longitudinal sectional view showing a first embodiment of a guide wire according to the present invention, and FIG. 2 is a view showing a procedure for connecting a first wire and a second wire in the guide wire shown in FIG. For convenience of explanation, the right side in FIG. 1 is referred to as a “base end” and the left side is referred to as a “distal end”. Also, in FIG. 1, the length direction of the guide wire is shortened to make it easier to see, and the thickness direction of the guide wire is schematically exaggerated, and the ratio of the length direction to the thickness direction is This is significantly different from the actual case (the same applies to FIGS. 5 to 7 described later).
[0033]
A guide wire 1 shown in FIG. 1 is a guide wire for a catheter used by being inserted into a catheter, and includes a first wire 2 disposed on a distal side and a second wire disposed on a proximal side of the first wire 2. It has a wire 3 and a spiral coil 4. The total length of the guidewire 1 is not particularly limited, but is preferably about 200 to 5000 mm. Further, the outer diameter of the guide wire 1 is not particularly limited, but is usually preferably about 0.2 to 1.2 mm.
[0034]
The first wire 2 is a wire having elasticity. The length of the first wire 2 is not particularly limited, but is preferably about 20 to 1000 mm.
[0035]
In the present embodiment, the first wire 2 has an outer diameter gradually decreasing portion 22 whose outer diameter gradually decreases toward the distal end in a portion on the distal end side. Thereby, in the outer diameter gradually decreasing portion 22 of the first wire 2, the rigidity (bending rigidity, torsional rigidity) can be gradually reduced in the distal direction, and as a result, the guide wire 1 has a favorable distal end portion. By obtaining flexibility, followability to blood vessels and safety can be improved, and bending and the like can be prevented.
[0036]
In the illustrated configuration, the first wire 2 has a tapered shape in which the outer diameter continuously decreases gradually toward the distal end over substantially the entire length. The taper angle of the tapered portion of the first wire 2 may be constant along the longitudinal direction or may change along the longitudinal direction.
[0037]
In the present embodiment, the outer diameter gradually decreasing portion 22 has a tapered shape in which the outer diameter continuously decreases at a substantially constant decreasing rate toward the distal end. In other words, the taper angle of the outer diameter gradually decreasing portion 22 is substantially constant along the longitudinal direction. Thereby, the change in the rigidity of the outer diameter gradually decreasing portion 22 along the longitudinal direction can be made more gradual (smooth). In addition, unlike such a configuration, the decreasing rate of the outer diameter toward the distal end of the outer diameter gradually decreasing portion 22 (the taper angle of the outer diameter gradually decreasing portion 22) may change along the longitudinal direction. For example, a portion where the reduction rate of the outer diameter is relatively large and a portion where the outer diameter is relatively small may be alternately formed a plurality of times. In this case, there may be a place where the reduction rate of the outer diameter toward the distal end of the outer diameter gradually decreasing portion 22 becomes zero.
[0038]
The proximal portion of the first wire 2 has a substantially constant outer diameter along the longitudinal direction. It should be noted that, unlike the illustration, the first wire 2 may be such that the outer diameter gradually decreases toward the distal end over substantially the entire length, that is, the first wire 2 may be such that substantially the entire outer diameter is gradually reduced. .
[0039]
The constituent material of the first wire 2 is not particularly limited. For example, various metal materials such as stainless steel can be used, but it is preferable to use an alloy (including a superelastic alloy) exhibiting pseudoelasticity. More preferably, it is an elastic alloy. The superelastic alloy is relatively flexible and resilient and hardly bends. Therefore, by forming the first wire 2 from a superelastic alloy, the guide wire 1 can have a sufficient amount at the distal end portion. Flexibility and resilience to bending are obtained, followability to a complicatedly curved or bent blood vessel is improved, and more excellent operability is obtained, and even if the first wire 2 repeats bending and bending deformation, Since the first wire 2 does not have a bending habit due to the restoring property, it is possible to prevent a decrease in operability due to the first wire 2 having a bending habit during use of the guide wire 1.
[0040]
Pseudoelastic alloys include those having a stress-strain curve due to tension in any shape, including those in which transformation points such as As, Af, Ms, and Mf can be remarkably measured and those in which they cannot be measured. (Strain) and almost all return to the original shape by removing the stress are included.
[0041]
Preferred compositions of the superelastic alloy include a Ni-Ti alloy such as a 49-52 atomic% Ni-Ni alloy, a 38.5-41.5 wt% Zn Cu-Zn alloy, and a 1-10 wt% X (X is at least one of Be, Si, Sn, Al, and Ga), and a 36-38 atomic% Al-Ni-Al alloy. Of these, particularly preferred are the above-mentioned Ni-Ti alloys.
[0042]
The distal end of the second wire 3 is connected (connected) to the proximal end of the first wire 2. The second wire 3 is a wire having elasticity. The length of the second wire 3 is not particularly limited, but is preferably about 20 to 4800 mm.
[0043]
The second wire 3 is made of a material having a higher elastic modulus (Young's modulus (longitudinal modulus), rigidity (transverse modulus), bulk modulus) than the constituent material of the first wire 2. Thereby, moderate rigidity (bending rigidity, torsional rigidity) is obtained for the second wire 3, and the guide wire 1 becomes so-called stiff, so that pushability and torque transmission are improved, and more excellent insertion operability. Is obtained.
[0044]
Further, the first wire and / or the second wire may be formed of a so-called composite material such as forming inner and outer layers with different materials. Even in such a case, it is preferable that the rigidity of the second wire is higher than that of the first wire.
[0045]
The constituent material (material) of the second wire 3 is not particularly limited, and stainless steel (for example, SUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, SUS302, etc.) All kinds), piano wires, cobalt-based alloys, pseudoelastic alloys and other various metal materials can be used.
[0046]
Among them, the cobalt-based alloy has a high elastic modulus when used as a wire and has an appropriate elastic limit. For this reason, the second wire 3 made of a cobalt-based alloy has particularly excellent torque transmission properties, and is unlikely to cause problems such as buckling. As the cobalt-based alloy, any alloy may be used as long as it contains Co as a constituent element. However, an alloy containing Co as a main component (Co-based alloy: the content of Co in the elements constituting the alloy) Is the alloy with the largest weight ratio), and it is more preferable to use a Co—Ni—Cr alloy. By using an alloy having such a composition as a constituent material of the second wire 3, the above-described effects become more remarkable. Further, since the alloy having such a composition has plasticity even when deformed at normal temperature, it can be easily deformed into a desired shape, for example, during use. In addition, the alloy having such a composition has a high modulus of elasticity and can be cold-formed even at a high elasticity limit. By having a high elasticity limit, it is possible to sufficiently prevent buckling and reduce the diameter. And have sufficient flexibility and rigidity to be inserted into a predetermined site.
[0047]
Examples of the Co-Ni-Cr-based alloy include an alloy having a composition of 28 to 50 wt% Co-10 to 30 wt% Ni-10 to 30 wt% Cr and the balance of Fe, and a part of the alloy is another element (substitution element). Are preferred. The inclusion of the substitution element exerts a specific effect according to the type. For example, by including at least one selected from Ti, Nb, Ta, Be, and Mo as a substitution element, the strength of the second wire 3 can be further improved. When an element other than Co, Ni, and Cr is included, the content (of the entire substitution element) is preferably 30 wt% or less.
Further, a part of Co, Ni, and Cr may be replaced with another element. For example, part of Ni may be replaced by Mn. Thereby, for example, the workability can be further improved. Further, a part of Cr may be replaced with Mo and / or W. As a result, the elastic limit can be further improved. Among the Co-Ni-Cr alloys, a Co-Ni-Cr-Mo alloy containing Mo is particularly preferable.
[0048]
The specific composition of the Co-Ni-Cr alloy is, for example, (1) 40 wt% Co-22 wt% Ni-25 wt% Cr-2 wt% Mn-0.17 wt% C-0.03 wt% Be-balance Fe (2) 40 wt% Co-15 wt% Ni-20 wt% Cr-2 wt% Mn-7 wt% Mo-0.15 wt% C-0.03 wt% Be- balance Fe, (3) 42 wt% Co-13 wt% Ni- 20 wt% Cr-1.6 wt% Mn-2 wt% Mo-2.8 wt% W-0.2 wt% C-0.04 wt% Be-balance Fe, (4) 45 wt% Co-21 wt% Ni-18 wt% Cr- 1 wt% Mn-4 wt% Mo-1 wt% Ti-0.02 wt% C-0.3 wt% Be-balance Fe, (5) 34 wt% Co-21 wt% Ni-14 wt% Cr-0.5 wt% Mn-6w % Mo-2.5wt% Nb-0.5wt% Ta- balance being Fe, and the like. The Co-Ni-Cr-based alloy referred to in the present invention is a concept that includes these alloys.
[0049]
Further, when stainless steel is used as a constituent material of the second wire 3, the guide wire 1 can obtain more excellent pushability and torque transmission.
[0050]
In the present invention, it is preferable that the first wire 2 and the second wire 3 are made of different kinds of alloys, and the first wire 2 is made of a material having a lower elastic modulus than the material of the second wire 3. It is preferred that it has been done. Thus, the guide wire 1 has excellent flexibility at the distal end portion and has high rigidity (bending rigidity and torsional rigidity) at the proximal end portion. As a result, the guidewire 1 obtains excellent pushability and torque transmission and secures good operability, and at the distal end side, obtains good flexibility and resilience to follow the blood vessel and ensure safety. Is improved.
[0051]
Further, as a specific combination of the first wire 2 and the second wire 3, the first wire 2 is made of a superelastic alloy, and the second wire 3 is made of a Co-Ni-Cr alloy or stainless steel. It is particularly preferred to do so. As a result, the above-mentioned effects become more remarkable.
[0052]
It is preferable to use a Ni-Ti alloy as the superelastic alloy constituting the first wire 2 from the viewpoint of flexibility and restorability on the tip side.
[0053]
The coil 4 is a member formed by spirally winding a wire (thin wire), and is installed so as to cover a portion of the first wire 2 on the distal end side. In the illustrated configuration, a portion on the tip end side of the first wire 2 is inserted into a substantially central portion inside the coil 4. Further, a portion on the tip end side of the first wire 2 is inserted in non-contact with the inner surface of the coil 4. In the illustrated configuration, the coil 4 has a slight gap between the spirally wound wires in a state where no external force is applied. However, unlike the illustrated example, the coil 4 is spirally wound in a state where no external force is applied. Wires wound in a shape may be densely arranged without gaps.
[0054]
The coil 4 is preferably made of a metal material. Examples of the metal material forming the coil 4 include stainless steel, superelastic alloys, cobalt-based alloys, noble metals such as gold, platinum, and tungsten, and alloys containing these. In particular, when the guide wire 1 is made of an X-ray opaque material such as a noble metal, X-ray opacity is obtained for the guide wire 1, and the guide wire 1 can be inserted into a living body while confirming the position of the distal end portion under X-ray fluoroscopy. Yes, it is preferable. Further, the coil 4 may be configured such that the distal end side and the proximal end side are made of different materials. For example, the distal end side may be formed of a coil made of an X-ray opaque material, and the proximal end side may be made of a coil made of a material that relatively transmits X-rays (such as stainless steel). In addition, the total length of the coil 4 is not particularly limited, but is preferably about 5 to 500 mm.
[0055]
The proximal end and the distal end of the coil 4 are fixed to the first wire 2 by fixing materials 11 and 12, respectively. Further, an intermediate portion (position near the tip) of the coil 4 is fixed to the first wire 2 by a fixing material 13. The fixing materials 11, 12, and 13 are made of solder (brazing material). The fixing materials 11, 12 and 13 are not limited to solder, but may be adhesives. Further, the method of fixing the coil 4 is not limited to the method using the fixing material, and may be, for example, welding. In addition, in order to prevent damage to the inner wall of the blood vessel, the distal end surface of the fixing material 12 is preferably rounded.
[0056]
In the present embodiment, since such a coil 4 is provided, the first wire 2 is covered by the coil 4 and has a small contact area, so that the sliding resistance can be reduced, and thus the guide wire can be reduced. 1 further improves operability.
[0057]
In the present embodiment, the coil 4 has a wire having a circular cross section. However, the present invention is not limited to this. For example, the wire has a cross section of an ellipse, a square (especially a rectangle), or the like. Is also good.
[0058]
In the guide wire 1, the first wire 2 and the second wire 3 are connected (fixed) to each other by welding. As a result, the welding portion (connection portion) 14 between the first wire 2 and the second wire 3 has a high bonding strength (joining strength), and therefore, the guide wire 1 has a torsion torque from the second wire 3 The pushing force is reliably transmitted to the first wire 2.
[0059]
In the present embodiment, the connection end face 21 of the first wire 2 to the second wire 3 and the connection end face 31 of the second wire 3 to the first wire 2 are each substantially perpendicular to the axial direction (longitudinal direction) of both wires. It is flat. Thereby, the processing for forming the connection end faces 21 and 31 is extremely easy, and the above-described effect can be achieved without complicating the manufacturing process of the guide wire 1.
[0060]
Note that, unlike the configuration shown in the figure, the connection end surfaces 21 and 31 may be inclined with respect to a plane perpendicular to the axial direction (longitudinal direction) of both wires, or may be concave or convex.
[0061]
The method for welding the first wire 2 and the second wire 3 is not particularly limited, and includes, for example, butt resistance welding such as spot welding using a laser and butt seam welding, but butt resistance welding. Is preferred. Thereby, the welding part 14 can obtain higher bonding strength.
[0062]
In such a guidewire 1, the second wire 3 has a small cross-sectional area 32 near the welded portion 14, the cross-sectional area of which is smaller than the cross-sectional area of the base end 23 of the first wire 2. In other words, the cross-sectional area of the portion (small cross-sectional area 32) from the connection end face 31 to a predetermined position on the base end side of the second wire 3 is larger than the cross-sectional area of the base end 23 of the first wire 2. It is getting smaller. In the present embodiment, the small cross-sectional area portion 32 has an outer diameter smaller than the outer diameter of the base end portion 23 of the first wire 2, so that the cross-sectional area is smaller than the cross-sectional area of the base end portion 23. ing. That is, the area of the connection end face 31 is smaller than the area of the connection end face 21.
[0063]
As described above, since the second wire 3 is made of a material having a higher elastic modulus than the first wire 2, if the outer diameter of the distal end of the second wire 3 is temporarily smaller than that of the proximal end 23 of the first wire 2. If the outer diameter is the same, the rigidity (bending rigidity, torsional rigidity) of the guide wire 1 changes sharply across the welded portion 14. On the other hand, in the present invention, the small cross-sectional area 32 is provided at the distal end of the second wire 3 and the rigidity (bending rigidity, torsional rigidity) at the small cross-sectional area 32 is reduced (reduced). The change in the rigidity (bending rigidity, torsional rigidity) in the vicinity including the welded portion 14 along the longitudinal direction can be moderate (smooth), and the guidewire 1 can obtain excellent operability.
[0064]
In the present embodiment, the small cross-sectional area portion 32 has a portion where the outer diameter of the small cross-sectional area portion 32 gradually decreases in the distal direction, that is, a portion in which the cross-sectional area gradually decreases in the distal direction. ing. Thereby, rigidity (bending rigidity, torsional rigidity) can be gradually reduced from the base end of the small cross-sectional area portion 32 to the distal end of the small cross-sectional area portion 32 toward the distal end. As a result, the guide wire 1 In addition, the change in the rigidity (bending rigidity, torsional rigidity) along the longitudinal direction can be made more gradual (smooth).
[0065]
In the illustrated configuration, the small cross-sectional area 32 has a tapered shape in which the outer diameter (cross-sectional area) gradually decreases in the distal direction over the entire length. The portion may have a portion having a constant outer diameter (cross-sectional area), and further, a portion having a constant outer diameter may have a portion whose outer diameter gradually increases toward the welded portion 14 at the tip side. In these cases, the same effects as above can be obtained. Specific examples of these configurations will be described later in detail.
[0066]
The length of the small cross-sectional area portion 32 (the length indicated by L in FIG. 1) is not particularly limited, but is preferably about 3 to 1000 mm, and more preferably about 3 to 300 mm. When L is in the above range, the change in rigidity (bending rigidity, torsional rigidity) along the longitudinal direction can be made more gradual (smooth) in the vicinity thereof including the welded portion 14.
[0067]
The small cross-sectional area 32 is formed such that the bending stiffness at the distal end (the connection end face 31) of the second wire 3 is substantially equal to the bending stiffness at the base end (the connection end face 21) of the first wire 2. Is preferred. This makes it possible to make the change in the rigidity along the longitudinal direction more gradual (smooth) in the vicinity thereof including the welded portion 14. The bending stiffness at the distal end of the second wire 3 is expressed by the second moment of area of the connection end face 31 (determined only by the shape and dimensions of the connection end face 31). ₂ And the Young's modulus of the constituent material of the second wire 3 is E ₂ And E ₂ I ₂ The bending stiffness at the base end of the first wire 2 is determined by calculating the second moment of area of the connection end face 21 (determined only by the shape and dimensions of the connection end face 21) by I ₁ And the Young's modulus of the constituent material of the first wire 2 is E ₁ And E ₁ I ₁ Is obtained.
[0068]
Further, the guide wire 1 of the present embodiment has a step filling member 6 that fills a step formed on the outer periphery of the welded portion 14. As a result, the step on the outer periphery of the welded portion 14 formed by the outer diameter of the distal end of the second wire 3 being smaller than the outer diameter of the proximal end of the first wire 2 is eliminated. A decrease in slidability can be prevented.
[0069]
In the illustrated configuration, the step filling member 6 covers the outer periphery of the small cross-sectional area portion 32, and its outer diameter is substantially constant along the longitudinal direction and its inner diameter gradually decreases toward the distal end. The guide wire 1 is shaped so that the outer diameter of the guide wire 1 in the vicinity thereof including the welded portion 14 and the small cross-sectional area portion 32 is substantially constant along the longitudinal direction. Thereby, the influence of the step on the slidability of the guidewire 1 can be more reliably eliminated.
[0070]
The constituent material of the step filling member 6 is not particularly limited. For example, various resin materials and various metal materials can be used. However, a relatively soft material ( For example, solder, plastic, wax, etc.) are preferable. Further, the form of the step filling member 6 is not limited to the illustrated configuration, and may be, for example, a coil-shaped member.
[0071]
In the present embodiment, the welding portion 14 is located closer to the base end than the base end of the coil 4, but unlike the drawing, the welding portion 14 is located closer to the distal end than the base end of the coil 4. May be.
[0072]
When the stiffness of the first wire is lower than the stiffness of the second wire, the size of the connection end faces 31 and 21 in FIG. 1 may be opposite.
[0073]
5 and 6 are longitudinal sectional views showing other examples of the configuration of the small cross-sectional area in the guide wire of the present invention.
[0074]
As shown in FIG. 5, the small cross-sectional area portion 32 has a first portion 32A whose outer diameter gradually decreases in the distal direction, and a distal portion of the first portion 32A whose outer diameter is in the distal direction. And a second portion 32 </ b> B that gradually increases toward the bottom. The outer peripheral surface at the boundary between the first portion 32A and the second portion 32B forms a continuous curved surface (a gentle surface) without any steps. With such a configuration, stress concentration on the boundary is prevented or reduced, and twisting and kink are more reliably prevented (kink resistance is improved).
[0075]
The maximum outer diameter of the second portion 32B is at the connection end face 31 at the distal end thereof, and this maximum outer diameter is substantially equal to the outer diameter of the base end (connection end face 21) of the first wire 2. That is, in the small cross-sectional area portion 32 shown in FIG. 5, the area of the welding surface of the welded portion 14 can be made larger than in the configuration shown in FIG. 1, and the welding strength can be improved. As a result, when a torsional torque or a pushing force is applied from the second wire 3 to the first wire 2, damage to the welded portion 14 due to stress concentration on the welded portion 14 or insufficient strength can be more reliably prevented.
[0076]
In such a small cross-sectional area portion 32, the length of the first portion 32A is L _A , The length of the second portion 32B is L _B And L _A Is L _B Greater than. That is, the taper angle of the first portion 32A is smaller than the taper angle of the second portion 32B.
[0077]
Specifically, the length L of the first portion 32A _A Is the length L of the second portion 32B _B Is preferably about 0.1 to 1000 times, more preferably about 1.0 to 1000 times, and still more preferably about 1.0 to 50 times. Under these conditions, stress concentration on the welded portion 14 can be suppressed, and a smooth transition in rigidity can be realized.
[0078]
The small cross-sectional area portion 32 shown in FIG. 6 has a third portion 32C having a substantially constant outer diameter between the first portion 32A and the second portion 32B. Is similar to that shown in FIG. The outer diameter of the third portion 32C is the smallest diameter portion in the small cross-sectional area portion 32.
[0079]
The small cross-sectional area portion 32 shown in FIG. 6 has the same operation and effect as the small cross-sectional area portion 32 shown in FIG. 5, but the small cross-sectional area portion 32 is particularly provided by providing the third portion 32C. The minimum diameter part is a fixed length (L below) _C 5) Since they exist continuously, the stress concentration on the smallest diameter portion in the small cross-sectional area portion 32 is reduced or dispersed as compared with the configuration shown in FIG. When a torsional torque or pushing force is applied to 2, the torsion, kink, breakage, and the like of the minimum diameter portion in the small cross-sectional area 32 can be more reliably prevented.
[0080]
The third portion 32C preferably has substantially the same rigidity as the vicinity of the base end 23 of the first wire 2. Further, since the outer diameter of the third portion 32 </ b> C is substantially equal to the outer diameter of the vicinity of the proximal end 23 of the first wire 2, the outer diameter of the third portion 32 </ b> C extends from the small cross-sectional area 32 to the proximal end of the first wire 2. 23, a smooth transition of rigidity is realized.
[0081]
The outer peripheral surface at the boundary between the first portion 32A and the third portion 32C and the outer peripheral surface at the boundary between the third portion 32C and the second portion 32B are respectively continuous curved surfaces without steps (smooth). Surface). Thereby, the same effect as described above can be obtained.
[0082]
Length L of first portion 32A _A And the length L of the second portion 32B _B Is preferably the same as described above. In addition, these and the length L of the third portion 32C _C Is not particularly limited, but L _B ≤L _C ≤L _A Or L _B ≤L _A ≤L _C It is preferred that
[0083]
Furthermore, in the present embodiment, the length L of the first portion 32A _A Is the length L of the second portion 32B _B It is preferably about 0.1 to 1000 times, more preferably about 0.1 to 10 times. Under these conditions, stress concentration on the welded portion 14 can be suppressed, and a smooth transition in rigidity can be realized.
[0084]
Further, in order to sufficiently reduce or concentrate the stress concentration on the minimum diameter portion while maintaining the strength of the small cross-sectional area portion 32, the length L of the third portion 32C is adjusted. _C Is preferably about 0.1 to 200 mm, more preferably about 1 to 50 mm.
[0085]
5 and 6, the outer periphery of the small cross-sectional area 32 may be covered with the above-described step filling member 6, and the same effect as described above can be obtained.
[0086]
Hereinafter, a procedure for joining the first wire 2 and the second wire 3 by butt seam welding, which is an example of butt resistance welding, will be described with reference to FIG. FIG. 3 shows procedures (1) to (3) when the first wire 2 and the second wire 3 are joined by butt seam welding.
[0087]
In procedure (1), the first wire 2 and the second wire 3 fixed (attached) to a butt welding machine (not shown) are shown.
[0088]
In procedure (2), the first wire 2 and the second wire 3 are connected to each other by applying a predetermined voltage by a butt welding machine to the connection end face 21 on the base end side of the first wire 2 and the distal end of the second wire 3. Is brought into pressure contact with the connection end face 31 on the side. Due to this pressure contact, a molten layer is formed at the contact portion, and the first wire 2 and the second wire 3 are firmly connected.
[0089]
In step (3), the protruding portion of the connection portion (welded portion 14) deformed by pressure contact is deleted. Next, the portion of the second wire 3 on the base end side of the welded portion 14, that is, the tip portion of the second wire 3 is polished to obtain a small cross-sectional area having a desired shape as shown in, for example, FIG. 1, FIG. 5 or FIG. A portion 32 is formed, that is, a small cross-sectional area portion 32 whose outer diameter gradually decreases in the distal direction or has such a portion.
[0090]
In addition, the tip of the second wire 3 is polished in advance to form a small cross-sectional area 32 having a desired shape (the outer diameter gradually decreases toward the tip or has such a portion). The welding may be performed by bringing the wire 2 into pressure contact with the wire 2.
[0091]
FIG. 3 and FIG. 4 are views showing a use state when the guidewire 1 of the present invention is used for PTCA operation.
[0092]
3 and 4, reference numeral 40 denotes an aortic arch, reference numeral 50 denotes a right coronary artery of the heart, reference numeral 60 denotes a right coronary artery opening, and reference numeral 70 denotes a vascular stenosis. Reference numeral 30 denotes a guiding catheter for reliably guiding the guide wire 1 from the femoral artery to the right coronary artery, and reference numeral 20 denotes a balloon catheter for expanding a stenosis having a balloon 201 that can be expanded and contracted at the distal end thereof. .
[0093]
As shown in FIG. 3, the distal end of the guidewire 1 is projected from the distal end of the guiding catheter 30, and inserted into the right coronary artery 50 from the right coronary artery opening 60. Further, the guide wire 1 is advanced, inserted into the right coronary artery from the distal end, and stopped at a position where the distal end exceeds the vascular stenosis 70. Thereby, the passage of the balloon catheter 20 is secured. At this time, the welded portion 14 of the guidewire 1 is located near the base of the aortic arch 40 (in a living body).
[0094]
Next, as shown in FIG. 4, the distal end of the balloon catheter 20 inserted from the proximal end side of the guide wire 1 is made to protrude from the distal end of the guiding catheter 30 and further advanced along the guide wire 1 to open the right coronary artery opening. It is inserted into the right coronary artery 50 from the portion 60 and stops when the balloon reaches the position of the vascular stenosis 70.
[0095]
Next, a balloon expansion fluid is injected from the proximal end side of the balloon catheter 20 to expand the balloon 201 and expand the vascular stenosis portion 70. By doing so, the deposits such as cholesterol adhering and depositing in the blood vessels of the blood vessel stenosis part 70 are physically spread out, and the obstruction of blood flow can be eliminated.
[0096]
<Second embodiment>
FIG. 7 is a longitudinal sectional view showing a second embodiment of the guide wire of the present invention. Hereinafter, a second embodiment of the guidewire of the present invention will be described with reference to this drawing, but the description will be focused on the differences from the above-described embodiment, and the description of the same matters will be omitted.
[0097]
In the guide wire 1 'of the present embodiment, the first wire 2 has the outer diameter gradually decreasing portion 22 and the outer diameter gradually decreasing portion 24 provided on the proximal side from the outer diameter gradually decreasing portion 22. As described above, the first wire 2 may have the outer diameter gradually decreasing portions formed at a plurality of portions.
[0098]
Further, in the present embodiment, a protruding portion 15 protruding in the outer peripheral direction is formed on the welded portion 14. By forming such a protruding portion 15, the bonding area between the first wire 2 and the second wire 3 is increased, and the bonding strength thereof is particularly high. Thereby, the torsion torque and the pushing force from the second wire 3 are transmitted to the first wire 2 more reliably.
[0099]
Further, by forming the protruding portion 15, for example, it is possible to more easily visually recognize the welded portion 14 between the first wire 2 and the second wire 3 under X-ray fluoroscopy. As a result, by confirming the X-ray fluoroscopic image, it is possible to easily and surely grasp the progress of the guide wire 1 ′ and the catheter in the blood vessel and the like, which contributes to shortening of the operation time and improvement of safety. Can be.
[0100]
Further, as described above, the first wire 2 and the second wire 3 are usually made of materials having different elastic moduli. For this reason, the provision of the protruding portion 15 allows the operator to easily and reliably recognize a portion where the elastic modulus of the guide wire 1 'changes relatively largely. As a result, the guidewire 1 'is excellent in operability, and can contribute to shortening of the operation time and improvement of safety.
[0101]
The height of the protruding portion 15 is not particularly limited because it depends on the outer diameter of the first wire 2 or the second wire 3, but is preferably 0.001 to 0.3 mm, and is preferably 0.005 to 0.05 mm. Is more preferred. If the height of the protrusion 15 is less than the lower limit, the above-described effects may not be sufficiently exerted depending on the constituent materials of the first wire 2 and the second wire 3. On the other hand, if the height of the protrusion 15 exceeds the upper limit, the inner diameter of the lumen to be inserted into the balloon catheter is determined. In some cases, the diameter must be reduced, and it may be difficult to sufficiently exert the physical properties of the second wire 3.
[0102]
In the configuration shown in FIG. 7, the protruding portion 15 has a substantially circular arc shape on one side (upper side in FIG. 7) and the opposite side (lower side in FIG. 7) in the longitudinal section. The welded portion 14 is located at the maximum outer diameter portion. Thereby, the area of the welding surface of the welded portion 14 can be increased, and there is an advantage that higher bonding strength (welding strength) can be obtained.
[0103]
However, in the present invention, it goes without saying that the shape of the protruding portion 15 and the position of the welding portion 14 with respect to the protruding portion 15 are not limited thereto. For example, the protruding portion 15 may have a non-circular (non-arc) shape such as a trapezoid or a triangle, respectively, in one side and the opposite side in the longitudinal section. Further, the protruding portion 15 may have an asymmetric shape on the base end side and the tip end side with respect to the welding surface (the connection end surfaces 21 and 31) of the welding portion 14. In addition, the protrusion 15 is such that the axial position of the welding surface of the welding portion 14 with respect to the protrusion 15 is not at the center as shown in FIG. It may be located at a position biased toward one wire 2). With such a configuration, stress concentration on the welded portion 14 can be prevented or reduced, and therefore, when a torsion torque or a pushing force is applied from the second wire 3 to the first wire 2, the welded portion is prevented from being concentrated. It is possible to more reliably prevent the welded portion 14 from being damaged by stress concentration on the welded portion 14.
[0104]
Moreover, the guide wire 1 'of this embodiment has the coating layer 7 on the outer surface (outer peripheral surface) side. Thus, the guidewire of the present invention may have a coating layer that covers all or a part of the outer surface (outer peripheral surface). Such a coating layer 7 can be formed for various purposes. As an example, the coating layer 7 can reduce the friction (sliding friction) of the guide wire 1 ′ and improve the slidability to improve the sliding property of the guide wire 1 ′. Operability may be improved.
[0105]
For such a purpose, the coating layer 7 is preferably made of a material capable of reducing friction. Thereby, the frictional resistance (sliding resistance) with the inner wall of the catheter used together with the guidewire 1 'is reduced, the slidability is improved, and the operability of the guidewire 1' in the catheter is improved. Become. In addition, since the sliding resistance of the guide wire 1 ′ is reduced, when the guide wire 1 ′ is moved and / or rotated within the catheter, the guide wire 1 ′ may be kinked (bent) or twisted, particularly in the vicinity of a weld. Kink and twist can be more reliably prevented.
[0106]
Examples of materials capable of reducing such friction include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyesters (PET, PBT and the like), polyamides, polyimides, polyurethanes, polystyrenes, polycarbonates, silicone resins, fluorine resins ( PTFE, ETFE, etc.), silicone rubber, various other elastomers (for example, thermoplastic elastomers such as polyamide-based and polyester-based) or composite materials thereof. (Composite material) is preferred, and PTFE is more preferred.
[0107]
Another preferable example of the material capable of reducing friction includes a hydrophilic material or a hydrophobic material. Among these, hydrophilic materials are particularly preferable.
[0108]
Examples of the hydrophilic material include a cellulose-based polymer, a polyethylene oxide-based polymer, and a maleic anhydride-based polymer (eg, a maleic anhydride copolymer such as a methyl vinyl ether-maleic anhydride copolymer). ), Acrylamide-based polymer substances (eg, polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA) block copolymer), water-soluble nylon, polyvinyl alcohol, and polyvinylpyrrolidone.
[0109]
Such a hydrophilic material often exhibits lubricity by wetting (water absorption) and reduces frictional resistance (sliding resistance) with the inner wall of the catheter used with the guide wire 1 '. Thereby, the slidability of the guidewire 1 'is improved, and the operability of the guidewire 1' in the catheter is further improved.
[0110]
Further, by providing such a coating layer 7, the step filling member 6 described above can be omitted or simplified. That is, since the covering layer 7 is formed so as to cover the step near the welded portion 14, even if the step filling member 6 is omitted or simplified, the sliding property of the guide wire 1 'due to the step is reduced. Can be sufficiently prevented.
[0111]
Such a coating layer 7 may be formed at the entire length of the guide wire 1 ′ or at a part in the longitudinal direction. However, it is formed so as to cover the welded portion 14, that is, at a portion including the welded portion 14. preferable.
[0112]
The covering layer 7 covers the small cross-sectional area portion 32 and the protrusion 15 and has a substantially uniform outer diameter. It should be noted that a gradual change in outer diameter that does not hinder use is also included in “substantially uniform outer diameter”.
[0113]
The thickness of the coating layer 7 is not particularly limited, but usually, the thickness (average) is preferably about 1 to 20 μm, and more preferably about 2 to 10 μm. If the thickness of the coating layer 7 is too thin, the purpose of forming the coating layer 7 may not be sufficiently exhibited, and the coating layer 7 may be peeled off, and the thickness of the coating layer 7 is too thick. If so, the physical properties of the wire may be impaired, and the coating layer 7 may be peeled off.
[0114]
In the present invention, a treatment (chemical treatment, heat treatment, or the like) for improving the adhesion of the coating layer 7 to the outer peripheral surface (surface) of the guide wire body (the first wire 2, the second wire 3, the coil 4, and the like). ) Or an intermediate layer capable of improving the adhesion of the coating layer 7 can be provided.
[0115]
In addition, the coating layer 7 may have a substantially constant composition at each portion, or may have a different composition. For example, the constituent material of the coating layer 7 may be different between at least a region (first coating layer) that covers the coil 4 and a region (second coating layer) on the base end side of the region. Further, the first coating layer and the second coating layer may be formed so that both are continuously formed in the longitudinal direction, as shown in the drawing, but the base end of the first coating layer and the second coating layer The tip may be separated, or the first coating layer and the second coating layer may partially overlap.
[0116]
FIG. 8 is a perspective view showing another configuration example of the small cross-sectional area of the second wire in the guide wire of the present invention.
[0117]
The small cross-sectional area portion 32 of the second wire 3 shown in FIG. 8A does not have a reduced outer diameter, and has the same outer diameter as a portion closer to the base end than the small cross-sectional area portion 32. . The small cross-sectional area portion 32 has a hollow portion 321, and the inner diameter of the hollow portion 321 gradually increases toward the distal end. That is, the hollow portion 321 has a shape like a cone (or a truncated cone). Since such a hollow portion 321 is formed, the small cross-sectional area portion 32 has a smaller cross-sectional area than the base end portion 23 of the first wire 2 and has a gradually decreasing cross-sectional area toward the distal end. Its stiffness (bending stiffness, torsional stiffness) also decreases gradually toward the distal end. In the present invention, even when the small cross-sectional area portion 32 is in the form shown in FIG. 8A, the same effect as in the above-described embodiment can be obtained. Furthermore, by forming the hollow portion 321 and reducing the cross-sectional area without changing the outer diameter, a step is formed in the welded portion 14 with the base end portion 23 of the first wire 2 without providing the step filling member 6. There is also the advantage that it does not occur. The hollow portion 321 may have a shape like a pyramid (or truncated pyramid). Further, in this case, the rigidity before and after the welded portion 14 changes more smoothly by welding such that a part of the base end portion 23 of the first wire 2 is inserted into the hollow portion 321 of the second wire 3. Therefore, the kink resistance is further improved.
[0118]
The small cross-sectional area 32 of the second wire 3 shown in FIG. 8B has a shape like a truncated pyramid (a truncated hexagon), and the size of a polygon (regular hexagon) of the cross-section is small. By gradually decreasing in the distal direction, the cross-sectional area gradually decreases in the distal direction, and the rigidity (bending rigidity, torsional rigidity) also gradually decreases in the distal direction. Even in the case where the small cross-sectional area portion 32 is in the form shown in FIG. 8B, the same effect as in the above-described embodiment can be obtained.
[0119]
As described above, the guide wire of the present invention has been described with respect to the illustrated embodiment, but the present invention is not limited to this, and each part constituting the guide wire has an arbitrary configuration capable of exhibiting the same function. Can be replaced by Further, an arbitrary component may be added.
[0120]
【The invention's effect】
As described above, according to the present invention, the first wire disposed on the distal end side and the second wire disposed on the proximal end side of the first wire and made of a material having a higher elastic modulus than the first wire With this arrangement, a guide wire having a flexible distal end portion and a rigid base end portion and having excellent pushability, torque transmission, and followability can be configured.
[0121]
In addition, since the first wire and the second wire are connected by welding, the connection strength of the connection portion (welded portion) is high, and the torsional torque and the pushing force can be reliably transmitted from the second wire to the first wire. it can.
[0122]
Further, by providing the small cross-sectional area portion in the second wire, the change in rigidity along the longitudinal direction of the portion including the weld portion along the longitudinal direction is gentle, and the kink (bending) and torsion near the weld portion are surely prevented. Can be prevented.
[0123]
In particular, by improving the shape of the small cross-sectional area portion, for example, by providing the first portion, the second portion, and further the third portion, the welding strength of the welded portion is increased and the small cross-sectional area portion is increased. In this case, local stress concentration can be reduced or dispersed, and kink and twist can be prevented more reliably.
[0124]
Thus, according to the present invention, a guidewire excellent in operability, kink resistance, and torsion resistance can be provided.
[0125]
Further, by forming the projecting portion in the welded portion, the connection strength of the connecting portion (welded portion) can be further increased, and the torsion torque and the pushing force can be more reliably transmitted from the second wire to the first wire. It becomes.
[0126]
When the coating layer is made of a material capable of reducing friction, the sliding property of the guide wire in the catheter or the like is improved, and the operability of the guide wire can be further improved. By reducing the sliding resistance of the guide wire, kink (bending) and torsion of the guide wire, particularly kink and torsion near the welded portion can be more reliably prevented.
[0127]
Further, by changing the constituent material of the coating layer at each part, a part having a partially increased sliding resistance can be provided, and the versatility of the guide wire is widened for the surgeon.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of a guide wire according to the present invention.
FIG. 2 is a view showing a procedure for connecting a first wire and a second wire in the guide wire shown in FIG. 1;
FIG. 3 is a schematic diagram for explaining an example of use of the guide wire of the present invention.
FIG. 4 is a schematic view for explaining an example of using the guide wire of the present invention.
FIG. 5 is a longitudinal sectional view showing another example of the configuration of the small cross-sectional area in the guidewire of the present invention.
FIG. 6 is a longitudinal sectional view showing another example of the configuration of the small cross-sectional area in the guide wire of the present invention.
FIG. 7 is a longitudinal sectional view showing a second embodiment of the guide wire of the present invention.
FIG. 8 is a perspective view showing another configuration example of the small cross-sectional area of the second wire in the guide wire of the present invention.
[Explanation of symbols]
1,1 'guide wire
2 First wire
21 Connection end face
22 Gradual reduction of outer diameter
23 Base end
24 Outer diameter gradually decreasing part
3 Second wire
31 Connection end face
32 Small cross section
32A first part
32B second part
32C third part
321 hollow
4 coils
6 Step filling material
7 Coating layer
11, 12, 13 fixing material
14 Welds
15 Projection
20 balloon catheter
201 balloon
30 Guiding catheter
40 Aortic arch
50 Right coronary artery
60 right coronary artery opening
70 Vascular stenosis

Claims (11)

A first linear wire disposed on the distal end side;
A linear second wire, which is disposed on the base end side of the first wire and is made of a material having a higher elastic modulus than the constituent material of the first wire,
The first wire and the second wire are connected by welding,
The second wire has a small cross-sectional area near the weld of the first wire and the second wire, the cross-sectional area of which is smaller than the cross-sectional area of the base end of the first wire. Guide wire. A first linear wire disposed on the distal end side;
A second linear wire disposed on the proximal end side of the first wire and having a higher rigidity than the first wire;
A welding portion where the first wire and the second wire are connected by welding, having a projecting portion projecting in an outer peripheral direction;
The second wire has a small cross-sectional area near the weld of the first wire and the second wire, the cross-sectional area of which is smaller than the cross-sectional area of the base end of the first wire. Guide wire. The guidewire according to claim 1, further comprising a coating layer provided so as to cover at least the welded portion. The guidewire according to claim 1, wherein an outer diameter of the small cross-sectional area is smaller than an outer diameter of a base end of the first wire. The guidewire according to any one of claims 1 to 4, wherein the small cross-sectional area has a portion whose cross-sectional area gradually decreases toward the distal end. The guide wire according to any one of claims 1 to 5, wherein the small cross-sectional area has a portion whose outer diameter gradually decreases in a distal direction. The small cross-sectional area portion has a first portion whose outer diameter gradually decreases in the distal direction and a second portion whose outer diameter gradually increases in the distal direction with respect to the first portion. The guidewire according to any one of claims 1 to 5, comprising a portion. The guidewire according to claim 7, wherein the small cross-sectional area portion has a third portion having a substantially constant outer diameter between the first portion and the second portion. The guidewire according to claim 7 or 8, wherein the length of the first portion is 0.1 to 1000 times the length of the second portion. The guide wire according to claim 1, wherein a bending rigidity at a distal end of the second wire and a bending rigidity at a proximal end of the first wire are substantially equal. The guidewire according to any one of claims 1 to 10, further comprising a step filling member that fills a step formed on an outer periphery of the welded portion.

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